1. Field
The present disclosure relates to technology for controlling time-to-live (TTL) in a global server load balancer.
2. Discussion of Related Art
In content delivery network (CDN) services for constructing a disaster recovery (DR) site to overcome local difficulties of a data center and improving transmission costs and transmission speed, a global server load balancer (GSLB) is a key technical element that is essentially used.
In an existing GSLB, an operator sets cache time-to-live (TTL) in advance, and in this case, there is a problem that, even if a domain name system (DNS) record is changed due to occurrence of a fault in a site, a delay may occur by a maximum TTL time until a corresponding change is propagated to a final user. To address this problem, a method that sets TTL to be significantly small or to be even zero may be considered. However, in this case, rapid propagation of a situation concerning the change in the DNS record or the like is possible, but in proportion thereto, the number of requests which come in the GSLB is also increased, and therefore the GSLB becomes unable to respond to the requests in an extreme case. Therefore, there are demands for a method that adjusts TTL to an optimal value within the level for satisfying stability of the GSLB and service quality standard.